1. Field of the Invention
The present invention relates to a multilayer circuit substrate formed by alternately stacking conductive layers and insulating layers, and more particularly, to a structure of a circuit pattern suitable for a high frequency circuit.
2. Description of Related Art
Conventionally, the technique disclosed in Patent Document 1, for example, has been known as a technique for forming transmission lines so as to intersect with each other in a multilayer circuit substrate. In the technique disclosed in Patent Document 1, transmission lines are formed to intersect with each other by disposing one transmission line in a conductive layer in the circuit substrate and by disposing the other transmission line in another conductive layer. Also, the configuration disclosed in Patent Document 1 is made for transmitting high-frequency signals, and therefore, a conductive layer having a large enough ground conductor is interposed between the transmission lines. This way, the transmission lines function as micro-strip lines, thereby having prescribed characteristic impedance. Also, by the ground conductor, interference between the transmission lines such as cross-talk is prevented, in other words, isolation between the transmission lines is ensured.